The present invention relates to vehicle braking systems and more particularly, to systems with anti-lock braking (ABS) and traction control (TCS) capability.
The subject of this application is related to the following co-pending patent applications: U.S. Ser. No. 08/362,227, entitled "Two-Position Three-Way solenoid Valve," U.S. Ser. No. 08/363,080 entitled "Hydraulic ABS Modulator" and U.S. Ser. No. 08/362,228 entitled "Brake System With Hydraulic ABS Modulator," all commonly assigned, filed on Dec. 23, 1994 and all three of which are hereby, specifically incorporated herein by reference.
Conventional vehicle fluid brake systems are characterized by providing the ability for effective wheel braking in response to manual application of force to a brake pedal actuator. The art has adapted the conventional vehicle fluid brake system to automatic control mechanisms which represent a combination of hydraulic and electrical control and provide advanced braking functions. One such mechanism, ABS, typically modulates the fluid pressure delivered to a vehicle wheel brake to prevent the brake from locking up in certain braking situations. Another such mechanism, TCS, typically modulates the fluid pressure delivered to a vehicle wheel brake to prevent spinning of a powered wheel to improve the traction that is exerted by the vehicle's drive wheels. When a vehicle is being braked or accelerated an ABS or TCS system operates to improve the force between each controlled wheel and the road surface for improved vehicle braking or acceleration.
The adaptation of conventional vehicle braking systems has presented the challenge to provide a competitive, integrated braking system that is capable of providing normal braking, anti-lock braking to and traction control operation for the various types of fluid braking systems available. The problem posed in developing an integrated ABS/TCS braking system is to provide optimum operation considering system response, adaptability and efficiency while concurrently avoiding unnecessary complexity and cost. This presents a significant challenge in the development of braking systems.